Apparatus for enhancing hobby servo performance

ABSTRACT

An apparatus is disclosed for enhancing the operation performance of a servo. The apparatus comprises a rotational enhancement mechanism configured to functionally engage an output shaft associated with the hobby servo and a support panel displaced from the servo and having a aperture formed therein for receiving the rotational enhancement mechanism.

The present application is based on and claims the benefit of U.S.Provisional Patent Application Ser. No. 60/659,941, filed on Mar. 9,2005, the content of which is hereby incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION

The present invention generally pertains to the hobby-mechanicalindustry. More specifically, the present invention pertains to means forimproving the mechanical capacity of a hobby servo.

A servo motor (a.k.a. simply a “servo”) is a device having a rotatableoutput shaft. The output shaft can typically be positioned to specificangular positions in accordance with a coded signal received by theservo. It is common that a particular angular position will bemaintained as long as a corresponding coded signal exists on an inputline. If the coded signal changes, the angular position of the shaftwill change accordingly. Control circuits and a potentiometer aretypically included within the servo motor casing and are functionallyconnected to the output shaft. Through the potentiometer (e.g., avariable resistor), the control circuitry is able to monitor the angleof the output shaft. If the shaft is at the correct angle, the motoractuates no further changes. If the shaft is not at the correct angle,the motor is actuated in an appropriate direction until the angle iscorrect.

There are different types of servo motors that include output shaftshaving varying rotational and torque capabilities. For example, therotational and/or torque capability of an industrial servo is typicallyless restricted than that of a hobby servo. That being said, hobbyservos are generally available commercially at a cost that is much lessthan that associated with industrial servos. Because hobby servos arerelatively small and inexpensive, they are popular within thehobby-mechanical industry for applications such as, but not limited to,hobby robotic applications and radio-controlled models (cars, planes,boats, etc.). One example of a hobby servo is the Futaba S-148 availablefrom Futaba Corporation of America located in Schaumburg, Ill.

Another restriction associated with hobby servos, or servos in general,is a lack of mechanical capacity. Servos are used in a variety ofapplications, some of which consist of applying heavy loads to theoutput shaft. In many cases, in addition to rotational loads, lateralforces which are perpendicular to the output shaft may be applied. Someloads which may be within the rotational capacity of the servo outputshaft may nonetheless applying lateral forces exceeding the strength ofthe output shaft. In some cases, damage such as shaft distortion orbreakage may result. As such, there is a need for means to improve themechanical capacity and durability associated with hobby servos.

SUMMARY OF THE INVENTION

Embodiments of an apparatus are disclosed for enhancing the operationalperformance of a servo motor. Embodiments include an apparatus forenhancing the operational performance of a hobby servo comprising arotational enhancement mechanism configured to functionally engage anoutput shaft associated with the hobby servo and a support paneldisplaced from the servo and having an aperture formed therein forreceiving the rotational enhancement mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective side view of an apparatus for enhancing theoperational performance of a hobby servo.

FIG. 2 is an exploded perspective side view of the apparatus of FIG. 1.

FIG. 3 is an exploded perspective side view of a rotational enhancementmechanism.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1 is a perspective side view of an apparatus 100 for enchaning themechanical capacity of a servo 102. Apparatus 100 comprises a frame 106mounted to servo 102 using spacers 110. In accordance with one aspect ofthe present invention, spacers 110 are secured such that they form asubstantially rigid connection between frame 106 and servo 102. In thismanner, frame 106 has relatively limited movement with respect to servo102. Securing spacers 110 is described in detail below.

Auxiliary shaft 104 is rotatably engaged to servo 102 and is supportedby frame 106 through the use of bushing 108 engaged to aperture 120(shown in FIG. 2). The support of auxiliary shaft 104 by frame 106,coupled with the substantially rigid connection between servo 102 andframe 106, allows for the substantial absorption of forces appliedperpendicular to auxiliary shaft 104. As a result, auxiliary shaft 104may withstand greater forces before damage or breakage occurs.

In accordance with another aspect of the present invention, frame 106comprises mounting apertures 116 for securing apparatus 100 in anoperating environment. In one embodiment, attachment mechanisms areinserted through apertures 116 and fastened to corresponding aperturesin the operating environment. Attachment mechanisms may include screws,bolts, clips, nails, rivets, or any other means for securing apparatus100. It is important to note that other attachment schemes may beutilized to secure apparatus 100 without departing from the scope of thepresent invention.

FIG. 2 is an exploded perspective side view of apparatus 100. Inaccordance with one aspect of the present invention, a spline receiver128 is configured to engage servo output spline 126. As is typically ofsome hobby servos, servo output spline 126 comprises a series of gearteeth. In other embodiments, servo output spline 126 can compriseengagement configurations other than gear teeth. In such embodiments,spline receiver 128 can be modified accordingly to accommodate outputspline 126.

As illustrated in FIG. 3, servo output spline 126 includes a pluralityof gear teeth disposed around the outer edge perimeter. Female splinereceiver 128 consists of an aperture formed through the approximatecenter axis of a spline mount plate 130 and is configured to engageservo output spline 126. Spline receiver 128 is, illustratively, anaperture having a series of teeth formed around the perimeter configuredto engage a corresponding set of teeth formed on servo spline 126.Spline mount plate 130 may be varied depending upon which splinereceiver 128 configuration is needed to accommodate a given spline 126.While it is common for servo spline 126 to have a 23, 24 or 25 toothconfiguration, any other spline configuration is within the scope of thepresent invention. In other embodiments, a different spline mount plate130 can be utilized depending upon which spline receiver 128configuration is needed to accommodate a given spline 126. In otherembodiments, a specialized spline receiver 128 configuration is providedto accommodate attachment to multiple spline 126 configurations. Itshould be noted that spline receiver 128 configurations other than thosesuitable for 23, 24 or 25 tooth configurations are within the scope ofthe present invention. For example, output spline 126 can comprise lessthan 23 gear teeth. In other embodiments, output spline can comprisemore than 25 gear teeth. Spline receiver 128 can be configured in anynumber of ways based on the configuration of servo output spline 126.

In addition to varied tooth configurations, the size of servo outputspline can also vary depending upon, for example, the choice of hobbyservo 102. In one embodiment, the diameter across the hobby servo outputspline 126 from its furthest points is exactly 6 millimeters. In anotherembodiment, the diameter across the hobby servo output spline 126 fromits furthest points is approximately 6 millimeters. In anotherembodiment, the diameter across the hobby servo output spline 126 fromits furthest points is less than 10 millimeters. In another embodiment,the diameter across the hobby servo output spline 126 from its furthestpoints is more than 10 millimeters. Any size hobby servo output splineis within the scope of the present invention. It is important to notethat female spline receiver 128 can vary depending upon servo outputspline 126 tooth configuration and/or diameter.

Mount plate 130 is engaged to output spline 126 using an attachmentmechanism 132, such as a screw, which is inserted through the centeraxis of a washer 134 and into the center axis of spline 126. Shaft hub136 is further affixed to spline mount plate 130 using attachmentmechanisms 138 inserted through spline mount apertures 140 at thesurface of spline mount plate 130 proximate to servo 102. Attachmentmechanisms 138 are secured to shaft hub 136 through hub apertures 142.In one embodiment of the present invention, a spacer 144, having anoverall diameter similar to that of spline mount plate 130, is affixedbetween the adjoining surfaces of shaft hub 136 and spline mount plate130 and is secured by attachment mechanisms 138 inserted thoughapertures 146. It is important to note that other attachment schemes arewithin the scope of the present invention.

In accordance with another aspect of the present invention, as wasmentioned above, spacers 110 are used to secure frame 106 to servo 102.Servo 102 includes attachment flanges 114 having apertures 124 formedtherein as is typical of most hobby servos. Apertures 124 are alignedwith openings formed in spacers 110, and attachment mechanisms 122 areinserted through apertures 124 thereby securing spacers 110 to servo102. The distal ends of spacers 110 are further connected to frame 106by attachment mechanisms 112 inserted through frame apertures 126. Inaccordance with one aspect of the present invention, spacers 110 areconfigured to extend slightly beyond the top edge of shaft hub 136 suchthat frame 106, when mounted to spacers 110, is in close proximity tothe top of shaft hub 136.

In accordance with another aspect of the present invention, shaftbushing 108 can be inserted into aperture 120 formed in frame 106 suchthat the larger diameter of bushing 108 engages the top surface of frame106.

FIG. 3 illustrates a portion of apparatus 100. Rotational enhancementmechanism 300 includes all components shown in FIG. 3 except servo 102.Further, some of the components illustrated in FIG. 3, such as bushing108 and spacer 144, are optional within rotational enhancement mechanism300. As illustrated in FIG. 3, rotational enhancement mechanism 300includes an auxiliary shaft 104 inserted through optional shaft bushing108 and into the aperture 154 formed in shaft hub 136. In oneembodiment, auxiliary shaft 104 extends beyond shaft hub 136 and intothe aperture 152 formed in spacer 144. As described with regard to FIG.2, rotational enhancement mechanism 300 includes an aperture 128 havingteeth formed around the inner perimeter surface configured to engage acorresponding set of teeth on servo output shaft 126. In anotherembodiment, screw 132 is utilized to secure rotational enhancementmechanism 300 to output spline 126.

In accordance with one embodiment of the present invention, mount plate130 having aperture 128 formed therein is attached to a shaft hub 136.Further, auxiliary shaft 104 is secured within shaft hub 136 such thatrotation of hub 136 is translated to auxiliary shaft 104. In oneembodiment, shaft hub 136 includes an adjustable diameter determined bythe position of adjustment mechanism 148 within hub aperture 150. Thus,adjustment mechanism 148 can be used to tighten shaft hub 136 therebysecuring auxiliary shaft 104 within hub 136. Of course, other attachmentschemes may be utilized and are within the scope of the presentinvention.

In accordance with another aspect of the present invention, auxiliaryshaft 104 may be utilized to drive a mechanical load. Examples include,but are not limited to, gears, sprockets, chains, rotatable arms, or anyother device. As was mentioned above, some mechanical applicationsrequire a servo having a greater axial shaft strength than thattypically associated with a hobby servo. The present invention pertainsto simple and inexpensive enhancements for hobby servos that are capableof improving the mechanical capacity of the output shaft.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1. An apparatus for enhancing the operational performance of a hobbyservo, comprising: a rotational enhancement mechanism configured tofunctionally engage an output shaft associated with the hobby servo; asupport panel displaced from the servo and having an aperture formedtherein for receiving the rotational enhancement mechanism; wherein therotational enhancement mechanism comprises a spline mount plateconfigured to functionally engage a hobby servo output spline havinggear teeth; and wherein the rotational enhancement mechanism comprises ashaft hub attached to the mount plate and configured to receive anauxiliary shaft.
 2. The apparatus of claim 1 wherein the rotationalenhancement mechanism comprises an auxiliary shaft and wherein theaperture formed in the support panel is configured to receive theauxiliary shaft.
 3. The apparatus of claim 2 wherein the rotationalenhancement mechanism further comprises a bushing positioned within theaperture and configured to receive the auxiliary shaft.
 4. The apparatusof claim 1 and further comprising at least one spacer positioned betweenthe support panel and the hobby servo.
 5. The apparatus of claim 1wherein the spline mount plate is configured to functionally engage ahobby servo output spline having more than twenty gear teeth.
 6. Theapparatus of claim 1 wherein the spline mount plate is configured tofunctionally engage a hobby servo output spline that has a gear teethconfiguration selected from a set of configurations that includes atwenty-three tooth configuration, a twenty-four tooth configuration, anda twenty-five tooth configuration.